NBR vs. PU

Attribute	NBR	PU
Material	Nitrile rubber	Polyurethane
Hardness	60-90 Shore A	70-95 Shore A
Elongation at Break	200-600%	400-700%
Tensile Strength	10-30 MPa	30-60 MPa
Temperature Range	-40°C to 120°C	-30°C to 80°C

Introduction

When it comes to choosing the right material for various applications, NBR (Nitrile Butadiene Rubber) and PU (Polyurethane) are two popular options that are often considered. Both materials have their own unique attributes and characteristics that make them suitable for different purposes. In this article, we will compare the key attributes of NBR and PU to help you make an informed decision.

Chemical Composition

NBR is a synthetic rubber that is made from a combination of butadiene and acrylonitrile. This composition gives NBR excellent resistance to oil, fuel, and other chemicals, making it a popular choice for applications where exposure to these substances is common. On the other hand, PU is a polymer that is made by reacting diisocyanates with polyols. PU is known for its high tensile strength and abrasion resistance, making it suitable for applications that require durability and toughness.

Physical Properties

One of the key differences between NBR and PU lies in their physical properties. NBR is known for its excellent resistance to oil and fuel, as well as its ability to withstand high temperatures. This makes NBR a popular choice for seals, gaskets, and O-rings in automotive and industrial applications. PU, on the other hand, has a higher tensile strength and abrasion resistance compared to NBR. This makes PU a preferred material for applications that require durability and toughness, such as conveyor belts and wheels.

Flexibility and Elasticity

When it comes to flexibility and elasticity, both NBR and PU have their own strengths. NBR is known for its excellent flexibility, which allows it to be easily molded into different shapes and sizes. This makes NBR a versatile material that can be used in a wide range of applications. PU, on the other hand, is known for its high elasticity, which allows it to return to its original shape after being stretched or compressed. This makes PU a suitable material for applications that require resilience and flexibility.

Cost and Availability

Cost and availability are important factors to consider when choosing between NBR and PU. NBR is generally more affordable than PU, making it a cost-effective option for applications that require resistance to oil and fuel. NBR is also widely available and can be easily sourced from various suppliers. PU, on the other hand, is slightly more expensive than NBR due to its higher tensile strength and abrasion resistance. However, PU is also readily available and can be found in a variety of grades and formulations to suit different applications.

Environmental Impact

Another important consideration when choosing between NBR and PU is their environmental impact. NBR is a synthetic rubber that is not biodegradable, which means that it can have a negative impact on the environment if not disposed of properly. PU, on the other hand, is a polymer that can be recycled and reused, making it a more environmentally friendly option. Additionally, PU is known for its durability and longevity, which can help reduce waste and minimize the need for frequent replacements.

Conclusion

In conclusion, both NBR and PU have their own unique attributes and characteristics that make them suitable for different applications. NBR is known for its excellent resistance to oil and fuel, while PU is valued for its high tensile strength and abrasion resistance. When choosing between NBR and PU, it is important to consider factors such as physical properties, flexibility, cost, availability, and environmental impact to determine which material is best suited for your specific needs. By understanding the key differences between NBR and PU, you can make an informed decision that will ensure the success of your project or application.